IUCN/SSC Otter Specialist Group Bulletin
©IUCN/SCC Otter Specialist Group
Volume 41 Issue 3 (October 2024)
Abstracts
A Survey of Otters in the Kholongchu and Upper Drangmechu Rivers, Eastern Bhutan
Pages 125 - 139 (Report)
Lam Norbu, Tandin Jamtsho, Karma Jamtsho, Pema Tenzin, and Ugyen Lhendup
Otter species are declining across their distribution range in asia. Only scanty information is available about the presence of otters in Bhutan. This study documents the presence of three otter species, the smooth-coated otter (Lutrogale perspicillata), the small-clawed otter (Aonyx cinereus) and eurasian otter (Lutra lutra), in the landscape of Trashigang forest division in Eastern Bhutan. Multiple techniques were used to document otter presence, including camera trap survey, sign survey, direct sighting, reliable photographic evidence, found specimens, and public consultation. Habitat disturbances including sand mining and quarry, unregulated fishing and hydropower construction were identified as significant threats to otters in the study region. Further systematic otter surveys are needed in the region and other parts of the country to make an accurate population assessment, understand threats, and develop effective conservation strategies for the protection of otter species in Bhutan.
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Photographic Evidence of Incidental Sightings of the Vulnerable Asian Small-Clawed Otter (Aonyx cinereus Illiger, 1815) in the Mixed Forest of Darjeeling and Kalimpong District as Part of Central Himalaya
Pages 140 - 153 (Report)
Shuvam Sharma, Albina Subba, Ganesh Pradhan, and Abhijit Chhetri
Direct incidental sightings and confirmed identification of A. cinereus was recorded for the first time with documented photographic evidence in the study areas. This new report of A. cinereus from subtropical humid type mixed forest (1294m a.s.l.) in District Darjeeling and from semi-temperate type forest (Elevation: 1924.35m a.s.l.) of District Kalimpong, in state West Bengal, India as a part of Bio-geographic Province 2C, Central Himalaya demonstrates that the distribution and ranging patterns of such vulnerable species is still patchy in India. The present study aims to fill up an immense knowledge gap on the distributional range of Asian small-clawed otter in human dominated vulnerable landscapes from the Central Himalaya.
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Sea Otter (Enhydra lutris) Reintroduction to the Oregon Coast, United States: Challenges and Unanswered Questions
Pages 154 - 180 (Article)
Elysha Iversen, Luke E. Painter, and Nicole Duplaix
Sea otters (Enhydra lutris), listed as Endangered by the IUCN, are an important keystone species. They have been absent from the Oregon coast of the United States for more than 100 years. The conservation community in western North America is exploring the possibility of reintroducing sea otters to this large section of their historic range. The U.S. Fish and Wildlife Service and the non-profit organization Elakha Alliance completed feasibility assessments and determined that reintroduction is feasible. Many challenges and questions remain. The question of which founder source to use, northern or southern, wild or surrogate-reared, is yet to be answered. An adaptive process during reintroduction allows scientists to optimize the founder source. Dispersal of reintroduced otters is often detrimental to translocation attempts. Dispersal may be mitigated by releasing juveniles that have not developed strong home range fidelity. Ecological risk assessments such as shark bite or predation (being researched), and disease and domoic acid exposure (assessed once a reintroduction site is determined) are important aspects of planning. Economic and technical concerns remain. Red sea urchin fisheries are expected to be negatively impacted by sea otter reintroduction. Other concerns yet to be resolved comprise funding and support infrastructure, including monitoring, stranding response, veterinary care, oil-response, and a possible surrogacy program. Not all questions can be answered before a reintroduction occurs. Previous reintroductions in North America account for more than 30% of the global sea otter population. These reintroductions were accomplished with considerably less information about sea otters than is known today, illustrating that success is possible even with unanswered questions.
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